Events

Life on the edge: the evolutionary biology of viruses

2 November 2012

Presented by Prof. Eddie Holmes, School of Biological Sciences, The University of Sydney

RNA viruses are of great biological importance because of their role as agents of human disease and their presumed similarity to some of the earliest replicating molecules. I will first present an overview of the 'rules' of evolutionary change in RNA viruses. The central concept here is that the major aspects of RNA evolution and life-history - from the way they organize their genomes to their ability to jump species boundaries - reflect an intrinsically high rate of mutation. For example, I will show that the process of genome evolution in RNA viruses is in a large part determined by a remarkably high rate of deleterious mutation, which acts to put a cap on maximum genome size. In the second part of my seminar I will examine how viruses emerge in new hosts and how virulence might evolve following a host jump. The key question here is what can we predict about viral emerge? Mathematical models suggest that when viruses like HIV or avian influenza jump into human populations, evolution in the subsequent epidemic(s) can make the disease more harmful or less harmful depending on the biological particulars. I will examine the canonical case study of the evolution of virulence - the attenuation of myxoma virus following its introduction as a biological control into the European rabbit populations of Australia and Europe. I will use comparative genomics on archived isolates to determine the molecular changes that underpin the virulence evolution seen in the two epidemics, in turn making general conclusions about the evolution of pathogen emergence and virulence.